Position indicator through acoustics

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a U.S. national phase under 35 U.S.C. 371 of International Patent Application No. PCT/US2013/078341, titled “Position Indicator Through Acoustics” and filed Dec. 30, 2013, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to indication of tool position in a well completion.

BACKGROUND

Oilfield operations can involve the use of various tools in a downhole environment located at a significant distance from a tool operator. During use, tools can need to be positioned in exact locations in a well. Failure to properly position tools in a well can cause significant and costly problems, including undesired damage to the tool and/or wellbore. It can be desirable to determine a position of a tool before performing additional operations. It can be difficult to obtain information about the position of tools used downhole. Accurate positioning of tools can be further desirable in wells having multizone completions.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of a system for determining a position of a tubing section according to one aspect.

<figref idref="DRAWINGS">FIG. 2</figref> is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section according to one aspect.

<figref idref="DRAWINGS">FIG. 3</figref> is a cross-sectional view of part of the tubing assembly of <figref idref="DRAWINGS">FIG. 2</figref> in which a projection engages a slidable mass generating a signal indicative of the determining position of the tubing section according to one aspect.

<figref idref="DRAWINGS">FIG. 4</figref> is a cross-sectional view of part of the tubing assembly of <figref idref="DRAWINGS">FIG. 2</figref> in which a slidable mass impacts a shoulder of a tubing section according to one aspect.

<figref idref="DRAWINGS">FIG. 5<i>a </i></figref>is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with an electronic signal generator and a magnetic sensor, according to one aspect.

<figref idref="DRAWINGS">FIG. 5<i>b </i></figref>is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with an electronic signal generator and an RFID sensor, according to one aspect.

<figref idref="DRAWINGS">FIG. 6</figref> is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with an electronic signal generator, according to another aspect.

<figref idref="DRAWINGS">FIG. 7<i>a </i></figref>is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with a spring-biased hammer, according to one aspect.

<figref idref="DRAWINGS">FIG. 7<i>b </i></figref>is a close-up cross-sectional view of part of the tubing assembly of <figref idref="DRAWINGS">FIG. 7<i>a </i></figref>in which the hammer head of a spring-biased hammer impacts a tubing section, according to one aspect.

<figref idref="DRAWINGS">FIG. 8</figref> is a schematic illustration of a tubing assembly for determining a position of a tubing section with multiple signal generators, according to one aspect.

<figref idref="DRAWINGS">FIG. 9</figref> is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with a series of grooves, according to one aspect.

<figref idref="DRAWINGS">FIG. 10<i>a </i></figref>is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with an atmospheric chamber, according to one aspect.

<figref idref="DRAWINGS">FIG. 10<i>b </i></figref>is a close-up, alternate view of part of the tubing assembly of <figref idref="DRAWINGS">FIG. 10<i>a </i></figref>with a J-slot in an external surface of a tubing section, according to one aspect.

<figref idref="DRAWINGS">FIG. 11</figref> is an alternate cross-sectional view of part of the tubing assembly of <figref idref="DRAWINGS">FIG. 10<i>a </i></figref>with multiple atmospheric chambers, according to one aspect.

<figref idref="DRAWINGS">FIG. 12<i>a </i></figref>is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with a double ended collet, according to one aspect.

<figref idref="DRAWINGS">FIG. 12<i>b </i></figref>is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with a double ended collet, according to one aspect.

<figref idref="DRAWINGS">FIG. 13</figref> is a cross-sectional view of part of a tubing assembly for determining a position of a tubing section with a sliding hammer, according to one aspect.

<figref idref="DRAWINGS">FIG. 14</figref> is a graphical representation of measurements from a tubing assembly for determining a position of a tubing section according to one aspect.

<figref idref="DRAWINGS">FIG. 15</figref> is a block diagram of a system for determining a position of a tubing section according to one aspect.

DETAILED DESCRIPTION

Certain aspects and features relate to methods and assemblies for determining a position of a tubing string or section of a tubing string downhole in a wellbore. In one aspect a recognizable signal can be generated downhole. The recognizable signal can be received at surface or on the rig floor and can indicate the position of a body relative to a tubing section.

The recognizable signal can be generated by a signal generator. A signal generator may be any device or assembly used to electrically or mechanically generate a signal used to indicate a tool's position. The signal generator can generate a pressure wave, such as a sound wave, upon being triggered. In one aspect, the signal generator can be a slidable mass contacting a shoulder of a tubing section to generate a pressure wave. In one aspect, the signal generator can be a spring-biased hammer contacting a solid shoulder to generate a pressure wave. In one aspect, the signal generator can be an electronic signal generator, controlled by a logic circuit board or a processor, that produces a sound. In one aspect, the signal generator can be an atmospheric chamber being flooded that results in a detectable sound. In one aspect, the signal generator can be a collet or other device passing over a profile of grooves, generating sounds as the collet or other device snaps into the grooves.

In some aspects, the signal generator can located on a first tubing string or a section thereof and can be triggered when a detectable portion of a second tubing section passes by the signal generator a part thereof. The detectable portion can interact with or be detected by the signal generator, thus triggering generation of the recognizable signal. The first tubing section can be positioned downhole relative to a second tubing section. The first tubing section can be a work string that is maneuverable relative to the second tubing section. The second tubing section can be a completion string that can remain downhole for the life of the well. In some aspects, the signal generator can be located on the second tubing section and the detectable portion can be located on the first tubing section. In some aspects, the second tubing section can be a work string maneuverable relative to a first tubing section, such as a completion string. As used herein, the term “body” may be used to refer to one of a first tubing section, a second tubing section, or a downhole tool.

The recognizable signal can be repeatable. The recognizable signal can be received at the surface of the wellbore by a hydrophone or similar device capable of receiving pressure wave. The hydrophone's receipt of the pressure wave can indicate the position of the tubing section.

In one aspect, the detectable portion is a detent mechanism. A detent can be a device or structure designed to provide mechanical pressure on another device or structure. The detent mechanism can be a snap ring, collet, or spring loaded detent that can be positioned around an outer surface of a first tubing section. The signal generator can include a slidable mass positioned within a recess on an inner surface of the second tubing section at a desired location. The slidable mass can be coupled to the second tubing section by a biasing device such as a spring or Belleville washer. The biasing device can be configured to give the signal generator a predetermined release load. As a first tubing section moves relative to a second tubing section, the detent mechanism can cause a mechanism on the second tubing section to generate a pressure wave. Examples of the mechanism generating the pressure wave can include a spring loaded hammer, a slidable mass in a profile, and a lug.

In some aspects the signal generator can be an electronic signal generator connected to a logic circuit board or a processor, both located in a recess of the first tubing section. In one aspect, the detectable portion is a passive or active RFID located in a recess of or on the second tubing section and the signal generator includes a sensor configured to detect the proximity of the passive or active RFID. In one aspect, detectable portion is a reflective surface located in a recess of or on the second tubing section and the signal generator includes a sensor configured to detect light reflected off the reflective surface. In some aspects, the reflective surface can be highly reflective to a specific wavelength and the sensor is configured to substantially only detect that specific wavelength, such that the signal generator does not generate a pressure wave when it passes other reflective surfaces not highly reflective to the specific wavelength. In some aspects, the reflective surface can be highly reflective to a specific wavelength and the signal generator can be configured to generate a particular pressure wave correlated to the particular reflective surface sensed, based on which specific wavelength was detected by the sensor.

In one aspect, the signal generator can be an atmospheric chamber located in the second tubing section and can have a port sealable by a moveable collet or other cover. A detectable portion of the first tubing section can contact the moveable collet or other cover and cause it to open the port, thus allowing the atmospheric chamber to be flooded. The sound of the atmospheric chamber being flooded can result in a detectable pressure wave. In one aspect, moving the moveable collet or other cover can result in the opening of a plurality of ports to a plurality of respective atmospheric chambers, thus generating a pattern of detectable pressure waves.

In one aspect, the signal generator can be a collet located on a first tubing section and the detectable portion can be profile of grooves on a second tubing section. The collet can be configured to be biased such that it snaps into each groove as it passes the profile of grooves. A pattern of detectable pressure waves can be generated as the collet passes over the profile of grooves.

In some aspects, a second tubing section can include multiple signal generators and a first tubing section can include at least one detectable portion. In such aspects, the signal generators can be positioned in patterns along the second tubing section such that a detectable pattern of pressure waves is generated when the second tubing section moves in relation to the first tubing section. In some aspects, multiple detectable portions can be positioned in patterns along the first tubing section and a second tubing section can include at least one signal generator. A detectable pattern of pressure waves can be generated when the second tubing section moves in relation to the first tubing section, as the signal generator is triggered by the plurality of detectable portions.

The pressure wave can travel to the surface and be detected by a hydrophone or other device capable of measuring a pressure wave. In one aspect, the pressure wave can be detected by the human ear or by touch. In one aspect, the pressure wave can travel through the formation fluid to the surface. In another aspect, the pressure wave can travel through the second tubing section to the surface. The hydrophone can indicate that the pressure wave was detected. The hydrophone's detection of the pressure wave can indicate that the first tubing section is at a specific location downhole relative to the second tubing section. The specific location can be known based on the known locations of the detectable portion within or on its tubing section and the signal generator within or on its tubing section. Detection by a hydrophone or other device capable of measuring a pressure wave can cause a display or annunciator panel to update. Detection of a particular pattern of pressure waves can cause a display, such as a computer monitor or annunciator panel, to update with identifying information correlating to the particular pattern of pressure waves detected. Such identifying information can include the location of the signal generator, location of the detectable portion, or the location of a tool attached to the first tubing section.

These illustrative examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative aspects but, like the illustrative aspects, should not be used to limit the present invention.

<figref idref="DRAWINGS">FIG. 1</figref> is a schematic view depicting a position indicator system <b>100</b> including a first tubing section <b>102</b> and a second tubing section <b>104</b>. The first tubing section <b>102</b> can include a detectable portion <b>106</b>. The first tubing section can include a tool <b>122</b>. In some aspects, the tool <b>122</b> may instead be included on the second tubing section. As used herein, any elements locatable on or in either a first tubing section <b>102</b> or a second tubing section <b>104</b> can instead be locatable on or in a tool <b>122</b>. The second tubing section <b>104</b> includes a signal generator <b>108</b> coordinating with the detectable portion <b>106</b>. A signal generator <b>108</b> and detectable portion <b>106</b> are said to be coordinating if the signal generator <b>108</b> is capable of generating a pressure wave <b>118</b> upon being triggered by the detectable portion <b>106</b>. The detectable portion <b>106</b> can trigger the signal generator <b>108</b> via a triggering event <b>110</b>. The triggering event <b>110</b> can be an event that involves physical contact between the tubing sections <b>102</b>, <b>104</b> or an event that involves the tubing sections <b>102</b>, <b>104</b> being in proximity to one another without physical contact occurring. Examples of a triggering event <b>110</b> involving physical contact can include mechanical pressure applied to or by the detectable portion, as described in further detail herein. Examples of a triggering event <b>110</b> that do not involve physical contact can include reflection of light, an RF link, or other similar triggering event without mechanical pressure, as described in further detail herein. The pressure wave <b>118</b> can be conducted to a hydrophone <b>114</b> through an acoustically conductible medium <b>124</b>. The acoustically conductible medium <b>124</b> can include the production fluid, the second tubing section <b>104</b>, and/or any other medium capable of conducting pressure waves. The hydrophone <b>114</b> can be acoustically connected to the signal generator <b>108</b> via the acoustically conductible medium <b>124</b>. Any sensor capable of detecting pressure waves can be utilized wherever the term “hydrophone” is used herein. In some aspects, the hydrophone or similar device is located downhole and/or incorporated into a downhole tool connected to the surface via wire.

Although <figref idref="DRAWINGS">FIG. 1</figref> depicts a tool <b>122</b> deployed via a tubing section <b>102</b> having a detectable portion <b>106</b>, other implementations are possible. Any configuration involving relative movement between a signal generator <b>108</b> (included in one of a moving tool string or station tubing section) and a detectable portion <b>106</b> (included in the other of a moving tool string or station tubing section) can be used as discussed herein. For example, a tool <b>122</b> may be included in a tool string deployed via wireline that includes a signal generator <b>108</b>.

The hydrophone <b>114</b> can be connected to a processor <b>116</b> that is connected to a display <b>120</b>. Upon receipt of the pressure wave <b>118</b> by the hydrophone <b>114</b>, the processor <b>116</b> can cause the display <b>120</b> to indicate the position of at least one of the first tubing section <b>102</b>, detectable portion <b>106</b>, second tubing section <b>104</b>, signal generator <b>108</b>, or a tool <b>122</b>.

In some aspects, the signal generator <b>108</b> is repeatable, meaning that the signal generator <b>108</b> is capable of resetting itself to generate further pressure waves <b>118</b> without human intervention. In some aspects, the signal generator <b>108</b> is partially repeatable, meaning that the signal generator <b>108</b> is capable of resetting itself a finite number of times before human intervention is necessary. In some aspects, the signal generator <b>108</b> is fully repeatable, meaning that the signal generator <b>108</b> is capable of resetting itself indefinitely, barring mechanical failure.

In some aspects, a signal indicating a position of a tool can be mechanically created by a slidable mass <b>214</b>. <figref idref="DRAWINGS">FIG. 2</figref> depicts a cross-sectional view of part of a tubing assembly <b>200</b> that includes the first tubing section <b>102</b> positioned relative to the second tubing section <b>104</b> downhole in a wellbore. The first tubing section <b>102</b> has a detectable portion <b>106</b> that is a detent mechanism <b>202</b>, such as a collet. In other aspects, the detent mechanism <b>202</b> can be a snap ring, a spring loaded detent, or other suitable device. The detent mechanism <b>202</b> is positioned within a recess on an outer surface <b>204</b> of the first tubing section <b>102</b>. The detent mechanism <b>202</b> includes a projection <b>206</b> that extends beyond the outer surface <b>208</b> of the first tubing section <b>102</b>.

The second tubing section <b>104</b> has a signal generator <b>108</b> positioned at a known location along the length of the second tubing section <b>104</b>. The signal generator <b>108</b> is positioned within a recess <b>210</b> on an inner surface <b>212</b> of the second tubing section <b>104</b>. The signal generator <b>108</b> includes a slidable mass <b>214</b> coupled to a spring <b>216</b>. The slidable mass <b>214</b> includes a projection <b>218</b> extending beyond the inner surface <b>212</b> of the second tubing section <b>104</b>. In other aspects, the spring <b>216</b> can be any suitable biasing device, for example, but not limited to, a Belleville washer. The spring <b>216</b> can provide a predetermined biasing force set such that the signal generator <b>108</b> can generate a pressure wave when a certain load is applied to the projection <b>218</b>. The projection <b>206</b> of the detent mechanism <b>202</b> can contact the projection <b>218</b> of the slidable mass <b>214</b> as the first tubing section <b>102</b> is maneuvered downhole relative to the second tubing section <b>104</b> towards the spring <b>216</b>.

<figref idref="DRAWINGS">FIG. 3</figref> depicts a cross-sectional view of part of a tubing assembly <b>200</b> with the projection <b>206</b> of the detent mechanism <b>202</b> contacting the projection <b>218</b> of the slidable mass <b>214</b>, causing the spring <b>216</b> to compress. The projection <b>206</b> of the detent mechanism <b>202</b> can contact and urge the projection <b>218</b> of the slidable mass <b>214</b> towards the spring <b>216</b> as the first tubing section <b>102</b> is moved relative to the second tubing section <b>104</b>. The spring <b>216</b> can compress as the detent mechanism <b>202</b> urges the slidable mass <b>214</b> towards the spring <b>216</b>. The projection <b>206</b> of the detent mechanism <b>202</b> can slide over and past the projection <b>218</b> of the slidable mass <b>214</b> when the force of the detent mechanism <b>202</b> against the slidable mass <b>214</b> exceeds the predetermined release load of the signal generator <b>108</b>. The spring <b>216</b> can uncompress and exert a force on the slidable mass <b>214</b> when the projection <b>206</b> of the detent mechanism <b>202</b> slides past and releases the projection <b>218</b> of the slidable mass <b>214</b>.

<figref idref="DRAWINGS">FIG. 4</figref> depicts a cross-sectional view of part of the tubing assembly <b>200</b> with the detent mechanism <b>202</b> forced past the slidable mass <b>214</b> and the slidable mass <b>214</b> contacting a solid shoulder <b>220</b> of the second tubing section <b>104</b>. When sufficient force is exerted against the slidable mass <b>214</b> by the detent mechanism <b>202</b>, at least one of the detent mechanism <b>202</b> and slidable mass <b>214</b> flexes or is displaced radially in order to allow the projection <b>206</b> of the detent mechanism <b>202</b> to move past the projection <b>218</b> of the slidable mass <b>214</b>. The spring <b>216</b> can expand when the projection <b>206</b> of the detent mechanism <b>202</b> moves past the projection <b>218</b> of the slidable mass <b>214</b>. The spring <b>216</b> can exert a force on the slidable mass <b>214</b> as the spring <b>216</b> expands. The slidable mass <b>214</b> can be moved along an axis in the direction of the force exerted by the expansion of the spring <b>216</b>. The slidable mass <b>214</b> can continue along the axis and contact a solid shoulder <b>220</b> of the second tubing section <b>104</b>. A pressure or sound wave can be generated by the slidable mass <b>214</b> contacting the solid shoulder <b>220</b>. The generation of the pressure wave can indicate that the first tubing section <b>102</b> is at a specific location or has passed the specific location with respect to the second tubing section <b>104</b>.

In alternative aspects, a signal indicating a position of a tool or tubing section can be electrically generated. <figref idref="DRAWINGS">FIG. 5<i>a </i></figref>is a cross sectional depiction of a part of tubing assembly <b>500</b> having a first tubing section <b>102</b> including a signal generator <b>108</b> that includes a magnetic sensor <b>502</b>, such as a hall effect sensor or a giant magnetoresistive sensor. The signal generator <b>108</b> further includes a processor <b>504</b>, a power supply <b>506</b>, and an electronic signal generator <b>508</b>. The electronic signal generator <b>508</b> can be any device capable of converting an electronic signal into a pressure wave, such as a loudspeaker or piezoelectric device. The tubing assembly <b>500</b> includes a second tubing section <b>104</b> with a detectable portion <b>106</b>. The detectable portion <b>106</b> includes a magnet <b>510</b>. The processor <b>504</b> can be configured to cause the electronic signal generator <b>508</b> to create an pressure wave <b>118</b> in response to the magnetic sensor <b>502</b> detecting the proximity of a magnetic field. As the first tubing section <b>102</b> is moved relative to the second tubing section <b>104</b>, the magnetic sensor <b>502</b> can pass by the magnet <b>510</b>, resulting in the generation of a pressure wave <b>118</b> that is indicative of the position of the first tubing section <b>102</b> relative to the second tubing section <b>104</b>. The processor <b>504</b> can be configured to generate a pressure wave <b>118</b> that includes a special pulsed signal that can be more easily distinguished, at the surface, from other noise. In some aspects, the processor <b>504</b> can further configure the electronic signal generator <b>508</b> to generate a pressure wave <b>118</b> that includes a special pulsed signal correlated to the detectable portion <b>106</b>. Such a special pulsed signal can be a unique signal.

In alternative aspects, a signal indicating a position of a tool or tubing section can be electrically generated. <figref idref="DRAWINGS">FIG. 5<i>b </i></figref>is a cross sectional depiction of a part of tubing assembly <b>500</b> having a first tubing section <b>102</b> including a signal generator <b>108</b> that includes an radio frequency identification (“RFID”) sensor <b>550</b>. The detectable portion <b>106</b> can include an active or passive RFID tag <b>552</b>. The RFID sensor <b>550</b> can be capable of detecting the proximity of the active or passive RFID tag <b>552</b>. In such an embodiment, a processor <b>554</b> can be configured to have the electronic signal generator <b>508</b> generate a pressure wave <b>118</b> in response to the RFID sensor <b>550</b> passing the RFID tag <b>552</b>. In some aspects, the RFID tag <b>552</b> can actively or passively transmit additional identifying information to the RFID sensor <b>550</b>. The additional identifying information can include a serial number, position information, or other information. In some aspects, the processor <b>554</b> can be configured to generate a pressure wave <b>118</b> that includes a special pulsed signal correlated to the additional identifying information. As used herein, a special pulsed signal that is correlated to the additional identifying information can include the additional identifying information or can be a unique signal otherwise recognizable as associated with the additional identifying information. In such aspects, the additional information can be conducted to the surface and the processor <b>116</b> at the surface can utilize the additional information to update a display <b>120</b> or perform some other action.

In some aspects, a unique signal can be generated that is used to identify where, at a number of predetermined locations within a tubing section, a body is located. The use of these unique signals can allow a user to identify a specific zone of a multi-zone completion in which the tool <b>122</b> is located. For example, a sensor <b>550</b> in communication with the processor <b>554</b> can sense the proximity of a first detectable portion of a tubing string or a section thereof. The processor <b>554</b> can receive data from the sensor <b>552</b> and configure the electronic signal generator <b>508</b> to generate a first pressure wave <b>118</b> or other signal. The first pressure wave <b>118</b> or other signal can correspond to or otherwise indicate a first location of a body of the tool <b>122</b> relative to a tubing string or a section thereof (e.g., a first zone of a multi-zone completion). The sensor <b>550</b> in communication with the processor <b>554</b> can subsequently sense the proximity of a second detectable portion of a tubing string or a section thereof. The processor <b>554</b> can receive data from the sensor <b>550</b> and configure the electronic signal generator <b>508</b> to generate a second pressure wave or other signal that can be differentiated from the first pressure wave or other signal. The second pressure wave or other signal can correspond to or otherwise indicate a second location of a body of the tool <b>122</b> relative to a tubing string or a section thereof (e.g., a second zone of a multi-zone completion).

In one aspect, as depicted in both <figref idref="DRAWINGS">FIGS. 5<i>a</i>-5<i>b</i></figref>, the first tubing section <b>102</b> can include a weigh down collet <b>520</b> and the second tubing section <b>104</b> can include an indicator <b>522</b>. Although depicted in <figref idref="DRAWINGS">FIGS. 5<i>a</i>-5<i>b</i></figref>, the weigh down collet <b>520</b> and indicator <b>522</b> as described herein can be utilized with other aspects described herein. The weigh down collet <b>520</b> can be located at a position deeper in a well bore than the signal generator <b>108</b>. The indicator <b>522</b> can be located at a position deeper in the well bore than the detectable portion <b>106</b>. The distance between the detectable portion <b>106</b> and the indicator <b>522</b> can be approximately equivalent to the distance between the signal generator <b>108</b> and the weigh down collet <b>520</b>. The weigh down collet <b>520</b> can locate and disengage the indicator <b>522</b>. A multi-zone completion assembly can have multiple indicators <b>522</b> corresponding to multiple zones. The use of a signal generator <b>108</b> in addition to a weigh down collet <b>520</b> can assist a tool operator in determining the position of the first tubing section <b>102</b> with respect to the second tubing section <b>104</b>. The signal generator <b>108</b> can additionally help diagnose problems with the weigh down collet <b>520</b> should it not properly locate the indicator <b>522</b>.

In additional aspects, the signal generator <b>108</b> may be triggered by reflected light. <figref idref="DRAWINGS">FIG. 6</figref> is a cross-sectional, schematic depiction of a part of tubing assembly <b>600</b> having a first tubing section <b>102</b> including a signal generator <b>108</b> that includes a light sensor <b>602</b> and a light source <b>604</b>. The signal generator <b>108</b> additionally includes a power supply <b>506</b>, a processor <b>504</b>, and an electronic signal generator <b>508</b>. The second tubing section <b>104</b> can include a reflective surface <b>606</b>. The light source <b>604</b> can be any source capable of emitting detectable light, such as an LED or a laser. The light source <b>604</b> can be angled with respect to the first tubing section <b>102</b> such that light emitted from the light source <b>604</b> bounces off the reflective surface <b>606</b> towards the light sensor <b>602</b>. In some aspects, the light source <b>604</b> can be not angled. In such aspects, the light source <b>604</b> and/or the reflective surface <b>606</b> can be diffuse enough to ensure some light emitted from the light source <b>604</b> is received by the light sensor <b>602</b>. The light source <b>604</b> can be monochromatic or polychromatic. The reflective surface <b>606</b> can be a specially treated surface of the inner diameter of the second tubing section <b>104</b>, or can be an element attached to or disposed within a recess of the second tubing section <b>104</b>. The reflective surface <b>606</b> can be configured to be highly reflective and capable of reflecting light from the light source <b>604</b> to the light sensor <b>602</b> when the signal generator <b>108</b> is proximate the detectable portion <b>106</b>. The reflective surface <b>606</b> can be configured to reflect only a particular wavelength of light or a narrow band of wavelengths of light. The processor <b>504</b> can be configured to cause the electronic signal generator <b>508</b> to create a pressure wave in response to the light sensor <b>602</b> detecting light reflected from the reflective surface <b>606</b>. As the first tubing section <b>102</b> is moved relative to the second tubing section <b>104</b>, the light source <b>604</b> and light sensor <b>602</b> can pass by the reflective surface <b>606</b>, resulting in the generation of a pressure wave, indicative of the position of the first tubing section <b>102</b> relative to the second tubing section <b>104</b>. The processor <b>504</b> can be configured to generate a pressure wave <b>512</b> that includes a special pulsed signal that can be more easily distinguished, at the surface, from other noise. The processor <b>504</b> can further be configured to generate a pressure wave <b>512</b> that includes a special pulsed signal correlated to the detectable portion <b>106</b>.

In one aspect, at least two reflective surfaces <b>606</b> can be located at different locations along the second tubing section <b>104</b>. Each of the reflective surfaces <b>606</b> can be configured to reflect a different wavelength or a narrow band of wavelengths of light. The narrow bands of wavelengths of light can be non-overlapping, such that no two reflective surfaces <b>606</b> reflect any of the same wavelengths of light. The light source <b>604</b> can be polychromatic, including at least each of the wavelengths or at least a portion of each of the narrow bands of wavelengths reflected by the reflective surfaces. The processor <b>504</b> can be configured to generate a pressure wave <b>512</b> that includes a special pulsed signal correlated to which wavelength or narrow band of wavelengths was detected by the light sensor <b>602</b>. The special pulsed signal would then identify which reflective surface <b>606</b> was passed by the signal generator <b>108</b>, thus enabling precise positioning of the first tubing section <b>102</b> relative to the second tubing section <b>104</b> at more than one location.

In several aspects, the signal generator <b>108</b> can include one or more wipers <b>608</b> positioned adjacent one or more of the light source <b>604</b>, the light sensor <b>602</b>, and/or the reflective surface <b>606</b>. The wipers <b>608</b> can be configured to clean any debris from the light source <b>604</b>, the light sensor <b>602</b>, and/or the reflective surface <b>606</b>. The wipers <b>608</b> can be powered. The wipers <b>608</b> can be passive and can be located on the opposite tubing section from the tubing section containing the object to be wiped.

In some aspects, a signal generator can be a hammer that mechanically impacts a tubing section. <figref idref="DRAWINGS">FIG. 7<i>a </i></figref>depicts a cross sectional view of a tubing assembly <b>700</b> having a signal generator <b>108</b> that includes a hammer <b>702</b> located in a recess <b>710</b> of a second tubing section <b>104</b>. The hammer <b>702</b> can include a hammer head <b>712</b> located across a pivot <b>704</b> from a cam <b>708</b>. The cam <b>708</b> can be spring biased away from the second tubing section <b>104</b>, such that the hammer head <b>712</b> is naturally biased towards a wall <b>714</b> of the recess <b>710</b> and the cam <b>708</b> is naturally biased past the inner diameter of the second tubing section <b>104</b>. The cam <b>708</b> can be configured to engage a detectable portion of a first tubing section, such as a detent mechanism. As the detent mechanism passes the cam <b>708</b>, it compresses the spring <b>706</b>, causing the hammer head <b>712</b> to move away from the wall <b>714</b>. Once the detent mechanism passes the cam <b>708</b>, the cam <b>708</b> can be released, allowing the hammer head <b>712</b> to fall against the wall <b>714</b>, as seen in <figref idref="DRAWINGS">FIG. 7</figref><i>b. </i>

<figref idref="DRAWINGS">FIG. 7<i>b </i></figref>depicts a close-up cross sectional view of part of the tubing assembly <b>700</b> of <figref idref="DRAWINGS">FIG. 7<i>a</i></figref>. A pressure wave <b>118</b> is generated in response to the hammer head <b>712</b> falling against the wall <b>714</b>.

In some aspects, a signal indicative of a position of a tool or tubing section can include a pattern of pressure waves. <figref idref="DRAWINGS">FIG. 8</figref> depicts a block diagram of a portion of a tubing assembly <b>800</b> including a second tubing section <b>104</b> having a pattern of signal generators <b>802</b>. The pattern of signal generators <b>802</b> can include a plurality of signal generators <b>108</b><i>a</i>-<b>108</b><i>n</i>. As a detectable portion <b>106</b> of a first tubing section <b>102</b> passes by the pattern of signal generators <b>802</b>, each of the signal generators <b>108</b><i>a</i>-<b>108</b><i>n </i>can generate its own pressure wave <b>118</b><i>a</i>-<b>118</b><i>n</i>. As the first tubing section <b>102</b> passes the second tubing section <b>104</b> at a relatively constant rate, the pressure waves <b>118</b><i>a</i>-<b>118</b><i>n </i>create a pattern of pressure waves <b>806</b>. The pattern of pressure waves <b>806</b> can be conducted to a hydrophone <b>114</b>. The particular pattern of pressure waves <b>806</b> received by a hydrophone <b>114</b> can be indicative of the location of the first tubing section <b>102</b> with respect to the second tubing section <b>104</b>. Additionally, multiple, unique patterns of signal generators <b>802</b> can be utilized in order to more precisely locate the position of first tubing section <b>102</b> with respect to the second tubing section <b>104</b> at multiple locations.

<figref idref="DRAWINGS">FIG. 9</figref> is a cross-sectional depiction of one aspect of a tubing assembly <b>900</b> having a detectable portion <b>106</b> including a series of grooves <b>904</b>. The series of grooves <b>904</b> can be incorporated into the inner diameter <b>906</b> of a second tubing section <b>104</b>. A first tubing section <b>102</b> can include a signal generator <b>108</b> including a detent mechanism <b>902</b> configured to be biased against the inner diameter <b>906</b> of the second tubing section <b>104</b>. As the first tubing section <b>102</b> moves with respect to the second tubing section <b>104</b>, the detent mechanism <b>902</b> can fall into each of the grooves <b>904</b> of the detectable portion <b>106</b>. A pressure wave can be generated in response to the detent mechanism <b>902</b> falling into a groove <b>904</b>. The pattern of grooves <b>904</b> within the detectable portion <b>106</b> can be correlated to a pattern of pressure waves caused by the movement of the signal generator <b>108</b> along the detectable portion <b>106</b>. In some aspects, multiple detectable portions <b>106</b> can be used in a tubing assembly <b>900</b>, each with a unique pattern of grooves <b>904</b> capable of resulting in a unique pattern of pressure waves. In these aspects, a first location of the first tubing section <b>102</b> with respect to the second tubing section <b>104</b> can be associated with a first pattern of pressure waves and a second location of the first tubing section <b>102</b> with respect to the second tubing section <b>104</b> can be associated with a second pattern of pressure waves. The first and second patterns of pressure waves can allow different positions in the wellbore to be identified.

In additional aspects, a signal indicative of a position of a tool or tubing section may be generated by flooding atmospheric chambers. <figref idref="DRAWINGS">FIG. 10<i>a </i></figref>depicts a cross sectional view of an aspect of a tubing assembly <b>1000</b> having a signal generator <b>108</b> including an atmospheric chamber <b>1002</b>. The atmospheric chamber <b>1002</b> can be filled with air or other fluid and can be known as a fluid chamber. The atmospheric chamber <b>1002</b> can be located on or in a first tubing section <b>102</b>. The atmospheric chamber <b>1002</b> can include a port <b>1008</b>. The port <b>1008</b> can be sealed by a sleeve <b>1004</b>. The sleeve <b>1004</b> can be axially movable within a recess <b>1012</b> of the first tubing section <b>102</b> to cover and uncover the port <b>1008</b>. The sleeve <b>1004</b> includes a projection <b>1006</b> extending past an outer diameter <b>1014</b> of the first tubing section <b>102</b>. An inner diameter, profile, or projection of a second tubing section <b>104</b> can indicate on the projection <b>1006</b>, causing the sleeve to move axially away from the atmospheric chamber <b>1002</b>, thus uncovering the port <b>1008</b>. Uncovering of the port <b>1008</b> can cause the atmospheric chamber <b>1002</b> to be flooded. A perceptible pressure wave can be created in response to flooding of the atmospheric chamber <b>1002</b>. In some aspects, the port <b>1008</b> can include an insert <b>1028</b> configured to tailor the pressure wave in response to fluid rushing into or out of the atmospheric chamber <b>1002</b>. The insert <b>1028</b> can be a whistle, a buzzing device (e.g., similar to a kazoo), or other such device capable of producing a recognizable pressure wave in response to fluid flow.

In some aspects, the first tubing section <b>102</b> can include a plurality of atmospheric chambers <b>1002</b>, <b>1024</b>, each having ports <b>1008</b>, <b>1010</b>, respectively. In some such aspects, the ports <b>1008</b>, <b>1010</b> are all covered and uncovered by the same sleeve <b>1004</b>. In some such aspects, a first atmospheric chamber <b>1002</b> would have a first port <b>1008</b> and a second atmospheric chamber <b>1024</b> can have a second port <b>1010</b>, spaced apart from the first port <b>1008</b> such that the first port <b>1008</b> and second port <b>1010</b> become uncovered by the sleeve <b>1004</b> sequentially, at different times. The first port <b>1008</b> and second port <b>1010</b> can be spaced apart axially. The sequential flooding of the atmospheric chamber <b>1002</b> can result in a unique pattern of pressure waves. In such aspects, the location of the first tubing section <b>102</b> with respect to the second tubing section <b>104</b> can be precisely known based on which pattern of pressure waves is detected.

<figref idref="DRAWINGS">FIG. 10<i>b </i></figref>is a close-up, alternate view of the tubing assembly <b>1000</b> of <figref idref="DRAWINGS">FIG. 10<i>a</i></figref>, showing a J-slot <b>1018</b> in an external surface of the first tubing section <b>102</b>. In some aspects, as seen in <figref idref="DRAWINGS">FIGS. 10<i>a </i>and 10<i>b</i></figref>, the sleeve <b>1004</b> can include a dog <b>1016</b> that fits within the J-slot <b>1018</b>. The sleeve <b>1004</b> can be biased to a covering position where the sleeve covers a first port <b>1008</b> and a second port <b>1010</b>. The J-slot <b>1018</b> can be shaped to have a plurality of limiting stops, such as a first stop <b>1020</b> and a second stop <b>1022</b>, located at successively further distances from the covering position. The J-slot <b>1018</b> functions to limit the range of travel of the sleeve <b>1004</b> to successively longer ranges of travel. In one aspect, the first stop <b>1020</b> is located closer to the covered position than the second stop <b>1022</b>. Upon reaching a limiting stop <b>1020</b>, <b>1022</b> in the J-slot <b>1018</b>, the sleeve <b>1004</b> or projection <b>1006</b> can compress or move to be positioned within the outer diameter <b>1014</b> of the first tubing section <b>102</b>. In some aspects, the detectable portion <b>106</b> can first cause the sleeve <b>1004</b> to travel to a first position, limited by the first stop <b>1020</b> in the J-slot <b>1018</b>, in which the first port <b>1008</b> is uncovered, allowing the atmospheric chamber <b>1002</b> associated therewith to flood. After the detectable portion <b>106</b> has passed, the sleeve <b>1004</b> can travel to a reset position <b>1026</b> in the J-slot <b>1018</b>. The reset position <b>1026</b> can be the covered position, or can be a position between the covered position and the first position. Thereafter, when a detectable portion <b>106</b> engages the projection <b>1006</b>, the sleeve <b>1004</b> travels to a second position, limited by a second stop <b>1022</b> in the J-slot <b>1018</b>, in which the second port <b>1010</b> is uncovered, allowing a second atmospheric chamber <b>1024</b> associated therewith to flood.

<figref idref="DRAWINGS">FIG. 11</figref> is a cross sectional depiction of an aspect of the tubing assembly <b>1000</b> of <figref idref="DRAWINGS">FIG. 10<i>a </i></figref>taken across line A:A. The first tubing section <b>102</b> is shown having multiple atmospheric chambers <b>1002</b><i>a</i>-<b>1002</b><i>g. </i>

A signal generator <b>108</b> that operates by flooding an atmospheric chamber <b>1002</b> can be desirable as it can be more resistant to negative effects of debris.

In some aspects, a signal indicative of a position of a tool or tubing section can be generated by a collet having a fluid-filled chamber. <figref idref="DRAWINGS">FIG. 12<i>a </i></figref>is a cross sectional depiction of an aspect of a tubing assembly <b>1200</b> utilizing a signal generator <b>108</b> having a collet <b>1202</b> and a chamber <b>1208</b> with a first side <b>1222</b> and a second side <b>1224</b>. A first tubing section <b>102</b> can include a collet <b>1202</b>. The collet <b>1202</b> is depicted as a double ended collet, although other types of collets can be used. The collet <b>1202</b> can include an external projection <b>1204</b> that extends past an outer diameter <b>1212</b> of the first tubing section <b>102</b>. The collet <b>1202</b> can be positioned in a recess <b>1218</b> of the first tubing section <b>102</b>. The collet <b>1202</b> can include two legs <b>1216</b> forming a chamber <b>1208</b> between the collet <b>1202</b> and the first tubing section <b>102</b>. The legs <b>1216</b> can include o-rings or other seals to ensure the chamber <b>1208</b> is tightly sealed such that the total volume of the chamber <b>1208</b> is substantially the same despite axial displacement of the collet <b>1202</b>. The chamber <b>1208</b> is substantially sealed and contains a fluid. The chamber <b>1208</b> can be known as a fluid chamber. Springs <b>1206</b> can be positioned within the recess <b>1218</b> to bias the collet <b>1202</b> in a neutral position, as shown in <figref idref="DRAWINGS">FIG. 12<i>a</i></figref>. When in the neutral position, an internal projection <b>1220</b> of the collet <b>1202</b> is located adjacent a block <b>1214</b> within the chamber <b>1208</b>. A pathway <b>1210</b> of restricted flow is located between the block <b>1214</b> and the internal projection <b>1220</b>. In the neutral position, the block <b>1214</b> and the internal projection <b>1220</b> separate the chamber <b>1208</b> into a first side <b>1222</b> and a second side <b>1224</b>, fluidly isolated except for the pathway <b>1210</b> of restricted flow. The pathway <b>1210</b> can include a valve. The pathway <b>1210</b> can include a small annulus. The pathway <b>1210</b> can be considered a displacement-selectively restrictive pathway because as the collet <b>1202</b> is displaced axially, the pathway <b>1210</b> changes from being highly restrictive to being less highly restrictive, as described in further detail below.

A detectable portion <b>106</b>, such as an inner diameter, profile, or projection of a second tubing section <b>104</b>, can indicate on the external projection <b>1204</b>, causing the collet <b>1202</b> to move axially within the recess <b>1218</b>. As the collet <b>1202</b> is pushed axially (e.g., from left to right as seen in <figref idref="DRAWINGS">FIG. 12<i>a</i></figref>), fluid within the chamber <b>1208</b> will move from one side to the other (e.g., from the first side <b>1222</b> to the second side <b>1224</b>) through the pathway <b>1210</b>. Because the chamber <b>1208</b> is sealed, fluid must flow between the first side <b>1222</b> and second side <b>1224</b> as the collet <b>1202</b> moves axially within the recess <b>1218</b>. The pathway <b>1210</b> can be configured to substantially restrict fluid flow only while the collet <b>1202</b> is not axially displaced beyond a predetermined set distance. When the collet <b>1202</b> is not axially displaced beyond the set distance, the pathway <b>1210</b> will restrict fluid flow between the first side <b>1222</b> and the second side <b>1224</b>. When the collet is in this first position, the pathway <b>1210</b> has a relatively high fluid resistance (i.e., resistance to fluid flow). Because the pathway <b>1210</b> allows only restricted flow between the first side <b>1222</b> and the second side <b>1224</b>, the collet <b>1202</b> will oppose being moved axially within the recess <b>1218</b>. Pressure will build up against the collet <b>1202</b>. After sufficient pressure is applied to the collet <b>1202</b>, the collet <b>1202</b> will be moved to a tripped position (e.g., axially displaced to a predetermined set distance) wherein the internal projection <b>1220</b> passes the block <b>1214</b> enough to widen the pathway <b>1210</b>. When in this tripped position, the pathway <b>1210</b> has a relatively low fluid resistance. The internal projection <b>1120</b> and/or the block <b>1214</b> can be shaped to allow the pathway <b>1210</b> to become free-flowing after the collet <b>1202</b> has been displaced axially by a sufficient amount. When the collet <b>1202</b> is in a tripped position (e.g., as seen in <figref idref="DRAWINGS">FIG. 12<i>b</i></figref>), the pathway <b>1210</b> allows significantly more fluid flow than in a neutral position (e.g., as seen in <figref idref="DRAWINGS">FIG. 12<i>a</i></figref>).

<figref idref="DRAWINGS">FIG. 12<i>b </i></figref>is a cross sectional depiction of the aspect of tubing assembly <b>1200</b> of <figref idref="DRAWINGS">FIG. 12<i>a</i></figref>, showing the collet <b>1202</b> immediately after being moved to a tripped position. Once the collet <b>1202</b> is in a tripped position, the built-up pressure will be quickly and forcefully released, causing one of the two legs <b>1216</b> to contact the block <b>1214</b> with sufficient force to generate a pressure wave <b>118</b>. After the detectable portion <b>106</b> passes the external projection <b>1204</b> of the collet <b>1202</b>, the collet <b>1202</b> can be biased back to its neutral position by springs <b>1206</b>.

In some aspects, the signal generator <b>108</b> can be configured to generate a pressure wave <b>118</b> in response to the detectable portion <b>106</b> passing the collet <b>1202</b> in either axial direction (e.g., left to right or right to left, as seen in <figref idref="DRAWINGS">FIGS. 12<i>a</i>-12<i>b</i></figref>). In some aspects, the signal generator <b>108</b> can be designed to only generate a pressure wave <b>118</b> in response to the detectable portion <b>106</b> passing the collet <b>1202</b> in only one of two axial directions (e.g., left to right or right to left, as seen in <figref idref="DRAWINGS">FIGS. 12<i>a</i>-12<i>b</i></figref>).

A signal generator <b>108</b> as described above in reference to <figref idref="DRAWINGS">FIGS. 12<i>a</i>-12<i>b </i></figref>can be beneficial as it can create a significant pressure wave in or from a first tubing section without substantially jarring a second tubing section.

In some aspects, a signal generator <b>108</b> can include a sliding hammer <b>1302</b> biased by a sealed chamber <b>1312</b>. <figref idref="DRAWINGS">FIG. 13</figref> is a cross sectional depiction of an aspect of a tubing assembly <b>1300</b> having a signal generator <b>108</b> that includes a sliding hammer <b>1302</b>. The sliding hammer <b>1302</b> can slide in an axial direction. The sliding hammer <b>1302</b> can be located in a recess <b>1318</b> of a first tubing section <b>102</b>. The sliding hammer <b>1302</b> can include a window <b>1320</b> between a first portion <b>1322</b> and second portion <b>1306</b>. A lug <b>1304</b> can be located within the window <b>1320</b>. A sealed, atmospheric chamber <b>1312</b> can be located between the sliding hammer <b>1302</b> and the first tubing section <b>102</b>. The atmospheric chamber <b>1312</b> can be sealed with O-rings. The lug <b>1304</b> can include a projection <b>1310</b>.

A detectable portion <b>106</b>, such as an inner diameter, profile, or projection of a second tubing section <b>104</b>, can interact with the projection <b>1310</b> to cause the lug <b>1304</b> to be pushed axially. As the lug <b>1304</b> is pushed axially (e.g., from left to right as seen in <figref idref="DRAWINGS">FIG. 13</figref>), it causes the sliding hammer <b>1302</b> to move in the same direction. As the sliding hammer <b>1302</b> moves, the volume of the atmospheric chamber <b>1312</b> expands or attempts to expand. The atmospheric chamber <b>1312</b> is filled with a fluid that resists an increase in volume of the atmospheric chamber <b>1312</b>. The resistance to the volume increase provides a biasing force that opposes the movement of the sliding hammer <b>1302</b> (e.g., provides a biasing force pulling the sliding hammer <b>1302</b> from right to left as seen in <figref idref="DRAWINGS">FIG. 13</figref>). The atmospheric chamber <b>1312</b> can be filled with an incompressible fluid. At a certain point, the lug <b>1304</b> falls within a recess <b>1316</b> of the first tubing section <b>102</b>, allowing the detectable portion <b>106</b> to move over the projection <b>1310</b> without pushing the lug <b>1304</b> or sliding hammer <b>1302</b> further. When the detectable portion <b>106</b> passes the projection <b>1310</b>, the biasing force from the atmospheric chamber <b>1312</b> is sufficient to pull the lug <b>1304</b> out of the recess <b>1316</b>, allowing the sliding hammer <b>1302</b> to contact the a shoulder <b>1314</b> of the first tubing section <b>102</b>. A perceptible pressure wave can be generated in response to the sliding hammer <b>1302</b> contacting the shoulder <b>1314</b> with sufficient force. The shoulder <b>1314</b> can include portion of the first tubing section <b>102</b> contacted by the sliding hammer <b>1302</b>, without limitation to the size, shape, or makeup of the shoulder.

In some aspects, the atmospheric chamber <b>1312</b> can be smaller in volume for deeper wells. In some aspects, another biasing device can be used in place of the atmospheric chamber <b>1312</b>, such as a spring or an elastomeric piece. In some aspects, another part can replace the lug <b>1304</b>, such as a collet.

In some aspects, a signal indicative of a position of a tool or tubing section can be validated. <figref idref="DRAWINGS">FIG. 14</figref> is a graphical depiction of both a first tubing section measurement <b>1402</b> and a pressure wave measurement <b>1406</b>, with respect to time, according to various aspects described herein. The graph of the first tubing section measurement <b>1402</b> depicts the tension and compression of the first tubing section <b>102</b> as the detectable portion <b>106</b> mechanically engages a signal generator <b>108</b>, according to various aspects described herein. The first tubing section measurement <b>1402</b> can be a weight measurement. The graph of the pressure wave <b>1404</b> depicts receipt of a pressure wave <b>118</b> by the hydrophone <b>114</b> or other device. In some aspects, a signal generator <b>108</b> can generate a pressure wave <b>118</b> at approximately time <b>1408</b>. A processor <b>116</b> can be configured to compare the timing of a first tubing section measurement <b>1402</b> and a pressure wave measurement <b>1406</b> to determine whether or not to update a display <b>120</b> or perform another function. In one aspect, the processor <b>116</b> is configured to update the display <b>120</b> or perform another action if a pressure wave <b>118</b> is detected in conjunction with an appropriate first tubing section measurement <b>1402</b> (e.g., with detecting an appropriate tension followed by a compression). The processor <b>116</b> can be configured to ignore other pressure wave <b>118</b> detections. The processor <b>116</b> can thusly be configured to validate any received pressure waves <b>118</b>.

In additional aspects, a signal indicative of a position of a tool or tubing section can originate as a mechanical action that is converted into an electrical signal that is electrically conducted to the surface from downhole. <figref idref="DRAWINGS">FIG. 15</figref> is a schematic depiction of an aspect of a position indicator system <b>1500</b> having a striking part <b>1502</b> and a struck part <b>1504</b>. The striking part <b>1502</b> can strike the struck part <b>1504</b> to mechanically generate a pressure wave <b>118</b> (e.g., the aspects depicted in <figref idref="DRAWINGS">FIGS. 2-4, 7</figref><i>a</i>-<b>7</b><i>b</i>, <b>9</b>, <b>12</b><i>a</i>-<b>13</b>). For example, the striking part <b>1502</b> can be a slidable mass <b>214</b> and the struck part <b>1504</b> can be a solid shoulder <b>220</b> of a second tubing section <b>104</b>.

In some aspects, the struck part <b>1504</b> can include an impact sensor <b>1506</b> connected to a processor <b>1508</b>. The impact sensor <b>1506</b> can detect generation of a pressure wave <b>118</b>. The impact sensor <b>1506</b> can be a strain gauge. The impact sensor <b>1506</b> can detect the generation of a pressure wave <b>118</b> in response to the striking part <b>1502</b> striking the struck part <b>1504</b>. Upon detection of the pressure wave <b>118</b>, the processor <b>1508</b> can send an electrical signal along an electrical conductor <b>1510</b> to a processor <b>116</b> at the surface. The electrical conductor <b>1510</b> can be at least partially contained within the first tubing section <b>102</b>.

In some aspects, the impact sensor <b>1506</b> includes electrical contacts that create an open circuit that is at least momentarily closed in response to the striking part <b>1502</b> striking the struck part <b>1504</b>.

A single tubing assembly can include one or more of the aspects described herein. As used herein, various signal generators <b>108</b> and detectable portions <b>106</b> located on or in a first tubing section <b>102</b> and second tubing section <b>104</b>, respectively, can be located on or in a second tubing section <b>104</b> and first tubing section <b>102</b>, respectively, and vice versa.

In some aspects, multiple signal generators <b>108</b> are used in a pattern to generate a discernible pattern of pressure waves <b>118</b>. In such aspects, multiple detectable portions <b>106</b> can be used with a single signal generator <b>108</b> to generate a discernible pattern of pressure waves <b>118</b>.

The foregoing description of the aspects, including illustrated aspects, of the invention has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of this invention.

Claims Bank

The following banked claims are part of the detailed description and are provided for illustrative purposes only.

Banked Claim <b>1</b>. An assembly comprising: a first tubing section including a detent mechanism positioned on an outer surface of the first tubing section; a second tubing section including a slidable mass coupled to a biasing device positioned on an inner surface of the second tubing section, wherein the first tubing section is positionable relative to the second tubing section such that the detent mechanism contacts the slidable mass as the first tubing section passes through the second tubing section, wherein the biasing device is responsive to the detent mechanism contacting the slidable mass by compressing, wherein the detent mechanism is responsive to the biasing device being compressed beyond a pre-determined threshold by moving past and releasing the slidable mass, wherein the slidable mass is responsive to being released by the detent mechanism by contacting a solid shoulder of the second tubing section.

Banked Claim <b>2</b>. The assembly of banked claim <b>1</b>, wherein the biasing device is one of a spring or a Belleville washer.

Banked Claim <b>3</b>. The assembly of banked claim <b>1</b>, wherein the biasing device is a spring.

Banked Claim <b>4</b>. The assembly of banked claim <b>1</b>, wherein the detent mechanism is selected from the group consisting of a snap ring, a collet, and a spring loaded detent.

Banked Claim <b>5</b>. The assembly of banked claim <b>1</b>, wherein the detent mechanism includes a first projection that extends beyond the outer surface of the first tubing section.

Banked Claim <b>6</b>. The assembly of banked claim <b>5</b>, wherein the slidable mass includes a complementary second projection that extends beyond the inner surface of the second tubing section and is complementary to the first projection.

Banked Claim <b>7</b>. The assembly of banked claim <b>1</b>, wherein the slidable mass is repeatedly responsive to being released by the detent mechanism by contacting the solid shoulder of the second tubing section.

Banked Claim <b>8</b>. The assembly of banked claim <b>1</b>, wherein the first tubing section is a work string including a tool and the second tubing section is a completion string.

Banked Claim <b>9</b>. The assembly of banked claim <b>1</b>, wherein the biasing device is responsive to the slidable mass being released by the detent mechanism by exerting a force against the slidable mass.

Banked Claim <b>10</b>. A method of determining a position of a tubing section at least partially disposed within a wellbore, the method comprising: disposing a first tubing section in the wellbore, the first tubing section including a slidable mass coupled to a biasing device positioned on an interior surface of the first tubing section; disposing a second tubing section relative to the first tubing section in the wellbore, the second tubing section including a detent mechanism positioned around an outer surface of the second tubing section; manipulating the second tubing section relative to the wellbore such that the detent mechanism contacts the slidable mass and compresses the biasing device; releasing the slidable mass in response to the biasing device being compressed beyond a pre-determined threshold; and driving the slidable mass into a solid shoulder of the second tubing section in response to releasing the slidable mass.

Banked Claim <b>11</b>. The method of banked claim <b>10</b>, further comprising, generating a sound wave in response to driving the slidable mass into the solid shoulder of the second tubing section and transmitting the sound wave through an acoustically conducting medium to a surface of the wellbore.

Banked Claim <b>12</b>. The method of banked claim <b>11</b>, wherein the acoustically conducting medium is the completion fluid.

Banked Claim <b>13</b>. The method of banked claim <b>11</b>, further comprising receiving by a receiver device the sound wave at the surface of the wellbore.

Banked Claim <b>14</b>. The method of banked claim <b>10</b>, further comprising uncompressing the biasing device when the slidable mass is released.

Banked Claim <b>15</b>. The method of banked claim <b>14</b>, further comprising forcing the slidable mass along an axis as the biasing device expands.

Banked Claim <b>16</b>. An assembly comprising: a first tubing section including a detent mechanism positioned on an outer surface of the first tubing section; a second tubing section including a slidable mass coupled to a biasing device positioned on an inner surface of the second tubing section, wherein the first tubing section is positionable relative to the second tubing section such that the detent mechanism contacts the slidable mass as the first tubing section passes through the second tubing section, wherein the biasing device is responsive to the detent mechanism contacting the slidable mass by compressing, wherein the detent mechanism is responsive to the biasing device being compressed beyond a pre-determined threshold by releasing the slidable mass, and wherein the slidable mass is responsive to being released by the detent mechanism by contacting a solid shoulder of the second tubing section.

Banked Claim <b>17</b>. The assembly of banked claim <b>16</b>, wherein the detent mechanism is selected from the group comprising a snap ring, a collet, and a spring loaded detent.

Banked Claim <b>18</b>. The assembly of banked claim <b>16</b>, wherein the biasing device is one of a spring or a Belleville washer.

Banked Claim <b>19</b>. The assembly of banked claim <b>16</b>, wherein the detent mechanism is responsive to the biasing device being compressed beyond the pre-determined threshold by releasing the slidable mass by pushing past the slidable mass.

Banked Claim <b>20</b>. The assembly of banked claim <b>16</b>, wherein the biasing device is responsive to the slidable mass being released by the detent mechanism by contacting exerting a force against the slidable mass as the biasing device expands.

Banked Claim <b>21</b>. The assembly of banked claim <b>16</b>, wherein the first tubing section is a work string having a tool and the second tubing section is a completion string, and wherein the detent mechanism is responsive to the biasing device being compressed beyond the pre-determined threshold by releasing the slidable mass in response to the tool being positioned at a specific location relative to the completion string.

Banked Claim <b>22</b>. An assembly comprising: a first tubing section including a signal generator and a weigh down collet; a second tubing section including a detectable portion and an indicator; wherein the signal generator is responsive to the detectable portion to generate a pressure wave; and wherein the weigh down collet is responsive to the indicator.

Banked Claim <b>23</b>. The assembly of banked claim <b>22</b> wherein the signal generation device includes an electronic signal generator.

Banked Claim <b>24</b>. The assembly of banked claim <b>23</b> wherein the detectable portion includes a magnet and the signal generator includes a sensor responsive to the magnet.

Banked Claim <b>25</b>. A method of determining a position of a tubing section at least partially disposed within a wellbore, the method comprising: positioning a first tubing section having a weigh down collet and a signal generator relative to a second tubing section having a detectable portion and an indicator; maneuvering the first tubing section relative to the second tubing section; detecting an interaction between the weigh down collet and the indicator; detecting a pressure wave generated by the signal generator in response to passing the detectable portion; determining the position of the first tubing section with respect to the second tubing section from both the detection of the interaction and the detection of the pressure wave.

Banked Claim <b>26</b>. A method of determining a position of a tubing section at least partially disposed within a wellbore, the method comprising: disposing a first tubing section in the wellbore, the first tubing section including a signal generator positioned on an interior surface of the first tubing section; disposing a second tubing section relative to the first tubing section in the wellbore, the second tubing section including a detectible portion; manipulating the second tubing section relative to the wellbore such that a pressure wave is generated by the signal generator in response to passing the detectable portion; and transmitting the sound wave through acoustic conducting medium to be received by a receiver device at the surface of the wellbore.